
67Physical Foundation of Interior Ballistics
Problem 20
Consider a shock tube that is 6 ft long with a diaphragm at the center. Air is contained in
both sections (γ = 1.4). The pressure in the high-pressure region is 2000 psi. The pressure in
the low pressure region is 14.7 psi. The temperature in both sections is initially 68°F. When
the diaphragm is burst, determine the following:
1. The velocity that the shock wave propagates into the low–pressure region.
Answer: 2798 [ft/s]
2. The induced velocity behind the wave.
Answer: 1946 [ft/s]
3. The velocity of a wave reected normally off the wall (relative to the laboratory).
Answer: 1232 [ft/s